One hominin trait that can be used to inform us about modern human biology are feet, though more specifically, toes. Toes are important because they can indicate how an organism lives and travels, whether it be through the trees or traversing across the land (also noting that a hominin is habitually bipedal). Looking at skeletal remains of feet and, in one case, the casts of footprints can allow us to look for clues of bipedal primates. If the big toe is divergent (further off to the side compared to the other toes), it’s likely that this organism was a tree-dweller, using the offset toe to aid in movement. However, if the abductable toe is lost (making the toe now inline with the other toes), this can be indicative of an organism who spends a decent amount, if not all, of their time on the ground. For example, the Laetoli Footprints, possibly left by Australopithecus afarensis, the very likely starting point for the species Homo, is a good representation of this change. The casted footprints depict a set of toes all inline with one another. This, paired with other bipedal traits shown in the prints and the with the simple fact that these prints are on the ground, can give us the sense that hominins were living below the trees at this point and, in doing so, needed the feet to support this lifestyle. Thus, each successive generation would adapt to this lifestyle and foot shape. And, if modern humans are descendants of A. afarensis, would lead us to how feet look today.

Another hominin trait we can look at are teeth. Teeth can have a variety of purposes but really we can boil these down to two: defense and eating (though here I am just really going to be focusing in on defense). Modern humans have, comparatively, small teeth and specifically, as mentioned in the lectures, the smallest canines of any primate. Looking backwards in time, we have a lot of dental remains and can see them progressively become more human-like. By physically seeing this change through time from species to species through the use of fossilized remains allows anthropologists to get a sense of behavioral traits of early hominins that would lead to changes in their anatomy. For example, we can start by looking at the species Ardipithecus kadabba. The dental remains of these early hominins show the larger, ape-like canines typically associated with defense. However, if we travel forward by about one million years to the second species, A. ramidus, we see a slightly smaller set of canines. This would indicate in a behavior shift, one that would involve defense and fighting tactics that do not utilize the teeth, therefore making larger canines obsolete. Jumping back into the present, we now have tiny canines and, at least to my knowledge (and in the adult-human sense, as some kids to resort to biting and this can be helpful against some attackers in dire situations) have moved beyond using our teeth as a primary weapon of self defense.

Both traits and their discovery can be attributed to fossilized remains (yes, even the footprints, as they were casted in volcanic ash!). These remains allow anthropologists to gather dates on them and place the hominin within a certain timeline (either through methods such as relative dating or absolute dating). In doing so, they can get a sense for how our ancestors had evolved to interact with their environment and those around them at a specific time.